Design of UCST Polymers for Chilling Capture of Proteins

Abstract

Ureido-derivatized polymers, such as poly(allylurea) (PU) and poly(L-citrulline) derivatives, exhibited upper critical solution temperature (UCST) behavior under physiological buffer conditions as we previously reported. The PU derivatives having amino groups (PU-Am) also showed UCST behavior. In this study, we modified the amino groups of the polymer with succinyl anhydride (PU-Su) or acetyl anhydride (PU-Ac) to determine the effects of these ionic groups on the UCST behavior and to control interactions between the PU derivatives and biocomponents such as proteins and cells. Succinylation of PU-Am resulted in a significant decrease in phase separation temperature (Tp), whereas acetylation of PU-Am resulted in an increase in Tp. As expected, the Tp of PU-Am and PU-Su changed when the pH of the solution was changed. The Tp of PU-Am increased at higher pH, whereas that of PU-Su increased at lower pH, indicating that ionic charge decreases Tp of PU derivatives by increasing osmotic pressure and by increasing hydrophilicity of the polymer chains. Interestingly, these groups did not significantly change UCST when these groups were nonionic. We then examined capture and separation of particular proteins from a protein mixture by cooling-induced phase separation. Selective and rapid capture of particular proteins from protein mixture by PU derivatives was shown, indicating that the ureido-derivatized polymers are potential media for bioseparation under biofriendly conditions.

Design of a Tunable Self‐Oscillating Polymer with Ureido and Ru(bpy)3 Moieties

“…[18][19][20] Briefly,p otassium cyanate was added to PA Aa queous solution, and the solution was stirred at 60 8 8Cf or 24 h. After the reaction,t he polymer was purified by dialysis in water,a nd obtained by lyophilization. [18][19][20] Briefly,p otassium cyanate was added to PA Aa queous solution, and the solution was stirred at 60 8 8Cf or 24 h. After the reaction,t he polymer was purified by dialysis in water,a nd obtained by lyophilization.…”

“…These polymers have applications as smart materials,i ncluding soft actuators,b iosensors,d rug delivery systems,a nd cell culture materials. [19,20] In this study,anovel UCST-type self-oscillating polymer was designed by introducing the catalyst for the oscillating chemical reaction into the PAU. [8,9] We have demonstrated the utility of self-oscillating materials as autonomous biomimetic materials,such as autonomous transport tubes, [10] artificial cells and amoeba composed of block copolymers, [11,12] and autonomous functional surfaces composed of polymer brushes.…”

“…To induce UCST-type behavior in aqueous solutions, polymer-polymer interactions must be stronger than polymer-solvent interactions at lower temperatures.I np revious studies,i th as been suggested that UCST-type polymers in aqueous media could be designed by introducing electrostatic interactions or hydrogen bonding to the polymer chains. [19,20] In this study,anovel UCST-type self-oscillating polymer was designed by introducing the catalyst for the oscillating chemical reaction into the PAU. [18] Thephase transition temperatures (T p )o fP AUsc an be regulated over aw ide temperature ranges (5-65 8 8C).…”

Postpolymerization synthesis of (bis)amide (co)polymers: Thermoresponsive behavior and self-association

“…[19][20][21][22][23][24][25][26][27][28] Of a wide variety of stimulus responsive (co)polymers prepared through postpolymerization modification techniques, only very few (co)polymer species exhibit aqueous UCST behavior. Examples include ureido-functional copolymers [29,30] and zwitterionic polysulfobetaines. poly(N-isopropylacrylamide) (pNIPAM).…”

Polymers from 1‐Vinyl‐2‐(hydroxymethyl)imidazole in Water: Altering from UCST to LCST Behavior via O‐Ethylation

“…The best‐known example is poly( N ‐acryloylglycinamide) (PNAGA), whose UCST behavior is based on hydrogen bonds. In this context, also copolymers of NAGA and homopolymers of other derivatives were investigated as well as ureido‐derivatived polymers . Thermoresponsive polymers can be used in the medical or biochemical field, for example, for drug release, bioseperation processes or swichtable hydrophobic–hydrophilic surfaces …”